Sliding form for casting columnar or box shaped concrete structures, such as chimneys, silos, and the like



Dec. 13, 1932. I c JESP'ERSEN 1,891,160

SLIDING FORM FOR CASTING COLUMNAR 0R BOX SHAPED CONCRETE STRUCTURES, SUCH AS CHIMNEYS, SILOS, AND THE LIKE Filed Feb. 16. 1931 2 Sheets-Sheet 1 Dec. 13,1932. I c JESPERSEN 1,891,160

SLIDING FORM FOR CASTING COLUMNAR 0R BOX SHAPED CONCRETE STRUCTURES, SUCH AS CHIMNEYS, SILOS, AND THE LIKE 2 Sheets-Sheet 2 Filed Feb. 16'. 19:51

L a M. C x/ Z a m] l Patented Dec. 13, 1932 UNITED STATES PATENT OFFICE OARSTEN' FBIIS JEsrERsnN, or BANGKOK, sr'au, AssIaNoa 'ro SVEND Fans JESPERSEN, or COPENHAGEN, DENuARx SLIDING FORM FOR CASTING- COLUHNAB R BOX SHAPED CONCRETE STRUCTURES,

SUCH AS CHIMNEYS, SILOS, AND THE LIKE Application filed February 16, 1931. Serial No. 516,237.

For casting of columnar or box-shaped concrete structures of relatively considerable height it is known to use sliding forms composed of an inner and outer form, between which the concrete is filled during slow continuous lifting of the form, gradually as the concrete deposited therein sets and hardens. The form is supported on vertical iron or steel-rods, which become imbedded in the 10 concrete, gradually as the concreting work progresses. 4

The heretofore known sliding forms of this nature are only suitable for casting of walls with uniform thickness. If the wall thickness is to be reduced in upward direction it has heretofore been necessary to use movable forms-of such a construction that the form members had to be altered, whenever they were moved. This use'of different forms in combination with the corresponding alterations is difiicult and time-Wasting.

The present invention relates to a sliding form for the production of building structures of the above mentioned nature with wall thickness decreasing gradually in upward direction, in such a manner that the same inner and outer form is used from the start to the finish of the concreting work.

.For this purpose the sections, into which the outer and inner form member are divided circumferentially in known manner, are interconnected by means of devices enabling the said sections to slide relatively to one another, in such a manner that the circumference of the two form members can be varied. The space between the two form connection with the said ribs or merely screwedon to the bolts, the edges of the sec tions can be approached to or removed from one another, whereby the circumference of the form will be increased or reduced. In order that the thus produced motion of two ad oiningsections may not result in an open gap, by way of which the poured concrete may escape, all such joints between two admeans for displacing the any two opposite brackets towards one another as well as away from one another when desired. v

The further details of the invention a pear from the following description of t e construction of a sliding form shown on the drawings.

Fig. 1 shows a horizontal section of a silo with circular cross-section, vertical outer face and sloping inner face, and a sliding form serving as a mould for casting the silo, in top view partly in section, Fig. 2 a vertical section of a portion of the wall of the silo and a sliding form for building the silo, in side elevation, and

Fig. 3 a clutch for attaching the sliding form to the vertical supporting rods.

The sliding form for constructing a silo shown on the drawings consists like other sliding forms of an inner. wall form a and an outer wall form I), which latter encircles the inner form, in such a manner that an annular space-is formed, between the inner and outer forms, for casting the silo wall.

Ea h of the two wall forms a and b is composed of sections, and the latter consist, in the construction shown, each of an angle-iron frame d and a plate e of steel or iron, the edges of which are connected to the frame d by riveting, welding or in any other suitable manner.

In the construction shown the angle-iron frames (1 of adjoining sections of the outer wall form are firmly interconnected by means of bolts f, in such a manner that the outer form forms a rigid integral annular unit. In order to give the outer form the requisite taper, planed wedges of steel or iron are inserted between the angle-iron frames of the individual sections. vThe said wedges cause the diameter of the finished outside form to be some inch larger on the lower edge than on the upper edge.

To each section of the outer form vertical posts 9 are attached, which may for instance be made from I-beams or channels. The connections between the posts 9 and the angleiron frames cl is efiected by means of angleiron splices ibolted to the angle-iron frame (2 and the post 9'.

Each post-g supports at top a transverse member h maintained in firm rigid connection with the post 9 by means of splice plates 7'. The transverse member 7!. supports or is made integral with a non-rotary nut k engaging a hollow screw Z.

The screws l in the transverse members It encircle, in known manner, each one of several vertical supporting rods m of iron or steel, for instance of 1" round rods. Each screw 1 is fitted, at its bottom end, with a shoe n, and the latter rests on a clutch 0 attached to the corresponding supporting rod m, Figs. 2 and 3. By rotation of the screws 1 the sliding form can in known manner be shifted up along the supporting rods. As shown by Fig. 1 the sections of the lnner wall form are assembled by means of bolts (I On these bolts pieces of channel lI'OIl c, are inserted between the angle-iron frames of the sections and carry inset plates 6 The latter cover the outside of the gaps etween any two adjoining sections of the lnner form. By rotation of the nuts of the bolts (L, the form parts will slide on the inset plate 6,, while either approaching one another or coming farther apart.

Vertical posts p, for instance in the same vertical planes as the posts g on the sections of the outer form, are attached to the sections of the the inner wall form and each post 71 carries a transverse member q. These transverse members rest each on one of the transverse members h of the posts 9 of the outer wall form. in such a manner that also the inner wall form will be lifted when the screws 1, passing freely through slots 1' in the transverse members are rotated and, thereby, pull the posts g and the outer wall form upward. In this manner both wall forms are elevated gradually as the space 0 between them becomes filled with concrete.

When the nuts during the elevation of the sliding form have reached the top ends of the corresponding screws Z, then some of these screws, for instance every other one, are screwed upward so as to leave the clutches 0. The said clutches, which consist each of two parts interconnected by means of a hinge s, Fig. 3, and pressed together about the rod on by means of a screw t, are thenby unscrewing the screws treleased sufficiently to enable them tobe pushed upward to a new position on the rods m, whereafter they are tightened up again. The screws 1 are then again brought to bear against the clutches 0. The other screws Z of the form are then adjusted in similar manner together with the corresponding clutches o, and the sliding form is now ready for a new lift etc.

During the pouring the screws Z are screwed continuously, in such a manner that the two wall forms a, b, in manner known per se, are slowly and simultaneously moved upward, gradually as the space 0 is fill-ed with concrete and the latter sets and hardens.

It should be noted that every other one of the screws 1 should have right-hand threads and every other one left-hand threads in order to prevent the entire form from ascending helically during the progress of the work. At the same timeas the screws 1 are rotated the nuts e, on the bolts (i, should also be rotated in such a manner that the wall thickness of the silo will be reduced graduallv as the form slides upward.

The posts p and 9 may be fitted with suitable platforms, on which the workmen can stand. Fig. 2 indicates by dotted lines the arrangement of supporting irons for a platform on the bottom end of the posts g, but there is of course nothing to prevent the provision of such .a platform at any desired level on the posts 9.

The vertical posts 9 are interconnected at top by means of two transverse girders or transverse beams 11 forming together with the posts 9 a rigid unit. An interior platform on which the workmen may stand during the operation may be disposed on top of the beams o.

It will be seen immediately that the relative tangential displacement of the sections of the inner wall form by rotation of the screws (1, will cause the entire inner wall form to be expanded and, consequently, to be adjusted in radialdirection. This adjustment mav suitably be supplemented by another adjustment in radial direction by means of other devices than the screws 11,. This object is attained by the provision of radially disposed screws :12 passing through holes in a member 11 interconnecting a beam 11' and a' cross-piece 2, Figs. 1 and 2, on a post 9. a

:otherwise shaped heads, the posts 1) can be removed from or approached to the wall u.

During the pouringvwork the screws :1: should normally be adjusted in such a manner that they do not exert any pressure, in either direction, on the posts 1).

The supporting rods m are joined in usual.

manner, gradually as they become imbedded in concrete u during the progress of the work. They are composed of pieces of unequal length, in such a manner that the various supporting rods m do not have to be spliced simultaneously during the work, but some of the rods are always held so securely in the concrete that they form a safe support for the entire form.

The pouring work is otherwise performed in known manner.

portant that the screws 1 are always rotated equally much and continuously, in such a manner that the forms will not take a skew position, whereby they would become pinched to the wall a. I

In the above the assumption was that the means for reducing the-thickness of the wall a were provided in connection with the inner form part a. There is, however, nothing to prevent the means of adjustment to be provided in connection with the outer wall form I) in exactly the same manner as described above for the inner wall form, in which case the outer wall form, gradually as the pouring work progresses and the sliding form ascends, must be contracted more and more, in order that the wall thickness may be reduced in upward direction. Finally, if desired, the means of adjustment may be used in connection with the outer as well as the inner wall form, in such a manner that the circumference of both of these wall forms may be.

reducedthe outer one more than the inner one-in such a manner that not only the wall thickness but also the diameter will be reduced in upward direction. Finally the sections of the two wall forms a and b may be I adjusted in such a manner, during the work, that the inner form is expanded and the outer form contracted, gradually as the work progresses. In this last mentioned case,

however, where both form parts are adjustable, the horizontal bracing 'v is omitted. In the above the invention is described in connection with forms for casting a silo of circular cross-section. but the invention is of It should benoted that it is highly imof the side faces of the form has to be divided into two or more parts adapted to be screwed together exactly in the same manner as the sections of the above described form.

On the drawings the two wall forms are each divided into six sections. However, it is within the scope of the invention to make the wall forms up of any suitable number of sections. In practice the number of the sections would ordinarily be larger than six.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed. I declare that what I claim is 1. A process of making columnar, hollow structures of considerable height, consisting in pouring a plastic material in the annular space between the outer and inner walls of a moldof smaller height than said structure,

using the same mold for forming the entire structure from the bottom to the top; gradually elevating the form as the pouring advances, and simultaneously gradually approaching the walls of the mold towards each one toprovide a continuous taper to the structure.

2. A mold for making concrete annular walls of considerable height comprising two spaced shells each consisting of circumferential series of sections, sliding joints interposed between adjacent sections of one shell permitting gradual adjustment of the circumferential length of the said shell, and means for gradually elevating the mold as a unit.

3. A mold for making concrete annular walls of considerable height comprising two spaced shells each consisting of circumferen: tial series of sections, a sliding joint inter posed between each section of one shell and the adjacent section of same; and means for gradually elevating the mold as a unit.

4. A mold for making concrete annular walls of-considerable height comprising two spaced shells each consisting of circumferential series of sections arranged at spaced intervals in one shell, overlapping plates covering the gaps "between consecutive spaced sections, adjustable means for gradually varying the width of the space between adjacent edges of the spaced sections, and. means for gradually elevating the mold as a unit.

mold for making concrete annular walls of considerable height comprising two spaced shells each consisting of a circumferential series of sections, means for supporting the two shells of the mold on vertical rods, means associated with the said supporting means and adapted to adjust the relative position of the two shells in a radial direction, means to elevate the supporting means gradually along vertically disposed rods, sllding joints between adjacent sections in one shell, and means for graduall varying the circumferential lengthof sai shell.

6. A mold for making concrete annular walls of considerable height comprising two spaced shells each consisting of a circumferential series of sections, means for supporting the two shells of the mold on vertical rods, means associated with the said supporting means and adapted to adjust the relative position of the two shells in a radial direction, means to elevate the supporting means grad ually along vertically disposed rods, sliding 13 joints between adjacent sections in each shell,

and means for gradually varying the circumferential length of the shells.

CARSTEN FRIIS JESPERSEN. 

